Functionalized Surface-Charged SiO₂ Nanoparticles Induce Pro-Inflammatory Responses, but Are Not Lethal to Caco-2...

Area of Science:

• Food science and nanotechnology
• Toxicology and cellular biology

Background:

• Nanoparticles (NPs) are increasingly used in food products.
• Assessing the potential gastrointestinal toxicity of NPs is crucial for food safety.

Purpose of the Study:

• To evaluate the effects of silica dioxide (SiO2), titanium dioxide (TiO2), and zinc oxide (ZnO) NPs on human monocyte-derived macrophages (THP-1) and colorectal adenocarcinoma cells (Caco-2).
• To investigate the impact of surface charge on SiO2 NPs' interaction and biological effects in Caco-2 cells.

Main Methods:

• Cell culture of THP-1 macrophages and Caco-2 cells.
• Exposure to varying doses of ZnO, TiO2, and SiO2 NPs.
• Assessment of reactive oxygen species (ROS) production, cell viability, nitric oxide (NO) levels, and interleukin-8 (IL-8) expression.
• Use of fluorescently labeled SiO2 NPs with neutral, positive, and negative surface charges.

Main Results:

• ZnO NPs demonstrated dose-dependent cytotoxicity and increased ROS production in both cell types.
• TiO2 and SiO2 NPs induced oxidative stress but were non-cytotoxic.
• Surface-charged SiO2 NPs exhibited increased interaction with Caco-2 cells, particularly negatively charged ones.
• Positively or negatively charged SiO2 NPs, but not neutral ones, elevated NO levels and upregulated IL-8 expression in differentiated Caco-2 cells.

Conclusions:

• Functionalized, surface-charged SiO2 NPs can elicit pro-inflammatory responses in intestinal cells without causing direct cytotoxicity.
• Different types of NPs exhibit varying toxicity profiles, with ZnO NPs being the most cytotoxic among those tested.